Timeguard 24hr Compact Immersion Time Switch - NTT01. The Timeguard NTT01 is a compact and efficient 24-hour electronic immersion heater timeswitch ideal for regulating hot water systems on a daily schedule. Operating on a 230 V AC / 50 Hz supply, it allows users to set up to 4 ON / 4 OFF switching periods per 24-hour cycle, giving flexibility to match hot water usage throughout the day. Its design supports both daily repeat mode and manual override, making it perfect for daily household routines or variable heating needs.. Designed for accessibility and ease of use, the NTT01 features a clear backlit display and intuitive button layout for programming. A self-cancelling override allows the heater to be temporarily bypassed and return to the programmed time at the next interval. The unit is built for both flush and surface mounting and fits within a standard wall box (with a minimum depth of approx. 32 mm). Its compact dimensions make it unobtrusive yet effective in a variety of installation locations.. With an internal relay rated at 16A (resistive loads), the NTT01 is capable of controlling immersion heaters, as well as other resistive appliances. It includes automatic summer/winter time adjustment, which ensures the times remain accurate as the clocks change, and a memory feature that retains programming for up to 100 hours during power interruptions. The combination of flexibility, reliability, and ease of installation makes the NTT01 a dependable choice for daily immersion control.